In recent years, cellular phones equipped with cameras have become dominant for domestic use, and thus small, thin and bright light sources for flashes capable of taking pictures even in dark places have been required. To meet this requirement, light-emitting diodes (LEDs) are promising. However, if light-emitting diodes are used under normal conditions, only insufficient luminance is obtained in many cases. To avoid this, attempts have been made to provide resin packages covering semiconductor light-emitting devices with a function as lenses.
Examples of use of resin packages as lenses include the following configurations. In Japanese Unexamined Patent Publication (Kokai) No. 1-273367 (pp. 1-4, FIG. 3) (hereinafter referred to as Reference 1), disclosed is a configuration in which a semiconductor light-emitting device mounted on a lead member is covered with a resin package and plating is performed on the convex surface of the resin package, thereby forming a concave mirror such that light is reflected from the surface of this concave mirror and released toward the back to be concentrated.
In Japanese Unexamined Patent Publication (Kokai) No. 8-306959 (pp. 2-3, FIG. 2) (hereinafter referred to as Reference 2), disclosed is a configuration in which a semiconductor light-emitting device mounted on a lead member is covered with a resin package and a recessed part and a convex lens part formed in this recessed part are formed on a light-emitting surface of the resin package so that light emitted toward the front of the semiconductor light-emitting device is released through the convex lens to be concentrated.
In Japanese Design Gazette No.: Similar Design 1 of Japanese Design Gazette No. 737044 (hereinafter referred to as Reference 3), disclosed is a configuration in which a recessed part and two convex lens parts formed in the recessed part are provided on a light-emitting surface of a resin package.
In Japanese Utility Model Publication No. 52-7580 (pp. 1-8, FIG. 6) (hereinafter referred to as Reference 4), disclosed is a configuration in which a light-emitting diode and a transparent part made of a synthetic resin are provided on the surface of a board so that this transparent part allows total reflection of light emitted from the light-emitting diode.
In Japanese Design Gazette No. 1051396 (A-A line cross-sectional view) (hereinafter referred to as Reference 5), disclosed is a configuration in which a semiconductor light-emitting device mounted on a lead member is covered with a resin package, the lead member projects toward the back, the base of the resin package is cylindrical and holds the lead member, and the diameter of the resin package gradually increases toward the front. In this configuration, total reflection of light emitted from the semiconductor light-emitting device toward the sides occurs at the peripheral face of the front part of the resin package, and the reflected light is released toward the front.